High energy ultrasonic lens assembly with mounting facets

• US 5,050,588 A
• Filed: 02/08/1990
• Issued: 09/24/1991
• Est. Priority Date: 02/08/1990
• Status: Expired due to Fees

• Current Assignee: Lithomed Technologies Inc.
• Original Assignee: Frank C. Ford, Richard Grey
• Inventors: Grey, Richard, Ford, Frank C.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Pfaffle, Krista M.
• Application Number:
  US07/476,874
• Time in Patent Office: 593 Days
• Field of Search: 128/24 A, 128/24 EL, 128/660.03, 128/662.03, 128/804, 128/399, 310/311, 310/335
• US Class Current: 601/4
• CPC Class Codes: B06B 1/0622 on one surface
• CPC Class Codes: G10K 11/30 using refraction, e.g. acoustic lenses
• CPC Class Codes: G10K 11/32 characterised by the shape of the source

Abstract

A lens assembly is formed by a curved dish or support member with piezo-electric transducers mounted on the concave outer surface. Flat mounting facets are machined on the outer surface to accommodate bonding between the transducer and the support member. A small concave focusing surface or lens for each transducer is machined on the concave inner surface of the support member directly opposite to the transducer and mounting facet. The focusing lenses are only slightly more convex than the inner surface of the support member, and the size of the focusing lenses is only a fraction of the size of the support member. Therefore, the path length of the energy from every point on every transducer to the invivo target region is almost identical. The energy arrives at the target region very closely in phase, forming a short pulse of maximum intensity.

Claims

1. A high energy ultrasonic device for in vivo treatment, comprising:

a rigid curved support means for defining an in vivo target region;

a convex outer mounting surface on the curved support means having a plurality of generally planar mounting facets formed thereon;

a plurality of electric to ultrasonic transducers mounted on the convex outer surface of the curved support means, each of said transducers having an inner mounting face which is generally planar for mounting onto one of the mounting facets, and each of said transducers having an outer contact face for connection to an electric voltage source;

each of said transducers having a major dimension extending generally parallel to the underlying mounting facet and a minor dimension extending generally normal to the underlying mounting facet;

electrical connector means for establishing an electric field across each of said transducers between the outer contact face and the inner mounting face for conversion into ultrasonic energy; and

a concave inner surface on the curved support means having a plurality of focusing means thereon, each one of said focusing means immediately opposed to each of said mounting facets on the outer surface, each of said focusing means forming an ultrasonic unit with each of the opposed mounting facets and each of the transducers mounted thereover to focus the ultrasonic energy from each of the transducers.

2. The ultrasonic device of claim 1 wherein each of said transducer-facet-focusing ultrasonic units is identical to each of the other ultrasonic units.

3. The ultrasonic device of claim 2 wherein each of the transducers is a round disk.

4. The ultrasonic device of claim 3 wherein the round disk transducers are arranged in a pattern of concentric hexagons of increasing size.

5. The ultrasonic device of claim 4 wherein the pattern of concentric hexagons increases in size in increments of six transducers.

6. The ultrasonic device of claim 5 further comprising:

a resilient cushion in the interstitial space between adjacent transducers.

7. The ultrasonic device of claim 4 wherein the pattern of concentric hexagons has a first hexagon containing 6 transducers, and a second hexagon containing 12 transducers, and a third hexagon containing 18 transducers, and a fourth hexagon containing 24 transducers.

8. The ultrasonic device of claim 6 wherein the pattern of concentric hexagons has a center transducer inside the first hexagon.

9. The ultrasonic device of claim 4 wherein each disk transducer is separated from the adjacent transducers in the same hexagon forming an intra-hexagon interstitial space, and separated from the adjacent transducers in the bordering hexagons forming an inter-border interstitial space.

10. The ultrasonic device of claim 9 wherein the intra-hexagon interstitial space diminishes slightly for each larger hexagon.

11. The ultrasonic device of claim 1 wherein the support means is symmetrically curved about a primary axis which passes through the target region defined by the support means.

12. The ultrasonic device of claim 11 wherein the curved support means is a segment of a true sphere with the target region at the center of curvature thereof.

13. The ultrasonic device of claim 11 wherein the curved support means is a segment of an oblate sphere with the target region at the center thereof.

14. The ultrasonic device of claim 11 wherein the normal center axis of each of the mounting facets in each said ultrasonic unit passes through a common point in the target region defined by the curve of the support means.

15. The ultrasonic device of claim 14 wherein the focusing means in each said ultrasonic unit is a curved focusing surface for defining a unit focal point along the normal center axis of each said ultrasonic unit.

16. The ultrasonic device of claim 15 wherein the relationship between the radius of curvature of the focusing surface and the radius of curvature of the support means is approximately

17. The ultrasonic device of claim 15 wherein the curved focusing surface in each said ultrasonic unit is formed on the concave inner surface of the curved support means.

18. The ultrasonic device of claim 15, wherein the curved focusing surface comprises:

a plurality of focusing caps mounted on the concave inner surface of the curved support means proximate each of the mounting facets within each of the ultrasonic units, each said cap having an inner mounting surface for engaging the concave inner surface of the curved support means, and each said cap having a curved outer focal surface for defining a focal point along the center axis of each of the ultrasonic units.

19. The ultrasonic device of claim 15 wherein the curve of the focusing surface is a true sphere.

20. The ultrasonic device of claim 15 wherein the curve of the focusing surface is an oblate sphere.

21. The ultrasonic device of claim 1 wherein the electrical connector means further comprise,

an outer electrode across the outer contact face of each transducer;

an inner electrode across the inner mounting face of each transducer;

outer distribution conductor means for connecting the outer electrode to one terminal of the electric voltage source; and

inner distribution conductor means for connecting the inner electrode to the other terminal of the electric voltage source.

22. The ultrasonic device of claim 21 wherein the outer electrode is a conductive mesh extending over outer contact faces of the transducers on the convex mounting surface of the curved support means.

23. The ultrasonic device of claim 22 further comprising a conductive epoxy for cementing the conductive mesh to each of the outer contact faces of the transducers.

24. The ultrasonic device of claim 21 wherein the curved support means is conductive and forms the inner electrode.

25. The ultrasonic device of claim 24 wherein the curved support means is formed of aluminum.

26. The ultrasonic device of claim 24 wherein the curved support means is formed of aluminum with an anodized layer thereover.

27. The ultrasonic device of claim 21 wherein the transducers are bonded to the support means by an epoxy, and the inner electrode is formed by a conductive additive in the epoxy.

28. The ultrasonic device of claim 21 wherein the outer electrode is connected to the high voltage side of the electric voltage source, and the inner electrode is connected to the ground side of the electric voltage source.

29. The ultrasonic device of claim 21 wherein the plurality of transducers are divided into sectors with an inter-transducer space between adjacent sectors, and the outer distribution conductor means provides a separate connection from the one terminal of the electric voltage source to each transducer sector.

30. The ultrasonic device of claim 29 further comprising insulative divider means in the inter-transducer space between adjacent transducer sectors.

31. The ultrasonic device of claim 29 wherein the inter-transducer space has a wedge cross-section with the wide portion of the wedge proximate the outer electrode and the narrow portion proximate the inner electrode.

32. The ultrasonic device of claim 29 wherein the transducers are arranged in a pattern of hexagons of increasing size.

33. The ultrasonic device of claim 32 wherein the sectors further comprise a central sector formed by the transducers at the vertices of the hexagons in the pattern, and six side sectors formed by the transducers between the vertices.